Trouble with BH1750 (Tiva C-Lm4f123gxl)

[asus0909 0]

#include <Wire.h> //BH1750 IIC Mode 
#include <math.h> 
int BH1750address = 0x23; //setting i2c address
uint16_t val=0;


byte buff[2];
void setup()
{
  Wire.begin();
  Serial.begin(9600);//init Serail band rate
}

void loop()
{
  
  int i;
  val=0;
  BH1750_Init(BH1750address);
  delay(200);

  if(2==BH1750_Read(BH1750address))
  {
    val=((buff[0]<<8)|buff[1])/1.2;
    Serial.print(val,DEC);     
    Serial.println("[lx]"); 
  }

}

   
int BH1750_Read(int address) 
{
  int i=0;
  Wire.beginTransmission(address);
  Wire.requestFrom(address, 2 );
  while(Wire.available()) 
  {
    buff[i] = Wire.read();  // receive one byte
    i++;
  }  
  
  Wire.endTransmission(); 
  return i;
}
  

void BH1750_Init(int address) 
{
  Wire.beginTransmission(address);
  Wire.write(0x10);//1lx reolution 120ms
  Wire.endTransmission();
}

SCL >> PA6

SDA >> PA7

 

but  no result ,pz help me?

[zeke 693]

@@asus0909

 

Here is a data sheet for the bh1750: http://www.dfrobot.com/image/data/SEN0097/BH1750FVI.pdf

 

The iic address = 0x23 when ADDR = LOW.

The iic address = 0x3C when ADDR = HIGH.

 

I do not see where you configure the light sensor for a specific sample resolution. It may be in reset mode until you configure it. Check out page 7 of the datasheet to see an example transaction to get a reading out of the device.

 

Also, do you have pull-up resistors on SCL and SCK?

[asus0909 0]

@@zeke

 

 

The iic address = 0x23 when ADDR = LOW.

this mean ADD >> GND ?

 

 

I do not see where you configure the light sensor for a specific sample resolution.

void BH1750_Init(int address) 
{
  Wire.beginTransmission(address);
  Wire.write(0x10);//1lx reolution 120ms
  Wire.endTransmission();
}

Wire.write(0x10);//Continuous_H_resolution_Mode  0x10

 

Can you help me code sample?

 

p/s:my english is not good

[zeke 693]

Hi @@asus0909,

 

Don't worry about your english skills. We can speak code and we will understand each other 

 

 

this mean ADD >> GND ?

 

Yes, that is correct. Connect the ADDR pin to ground and then the I2C address will be 0x23.

 

 

 

Do you have a logic analyzer?

 

If so, connect it up to the SDA and SCL lines and capture some waveforms. Those waveforms will let us know what is and is not working properly.

 

 

[asus0909 0]

 

 

Do you have a logic analyzer?

i don't have...

i use I2C_SoftwareLibrary.h  http://forum.43oh.com/topic/3617-energia-library-software-i2c-master-for-msp430g2553/ but error

 error: '__delay_cycles' was not declared in this scope

 

pz,help me?

[Marvi 1]

I tested BH1750FVI board for arduino and it works. But there is few things I have to do before It worked. On the board is 3.3V voltage stabilizer, so you must remove it or use 5V from USB and common ground with microprocessor! 

I make few changes in code. Energia 0014 and Launchpad 1.4 (cross RX TX) with MSP430G2553.

Here is my working code:

// SDA to PIN 1.7
//SCL to PIN 1.6
//The iic address = 0x23 when ADDR = LOW; address = 0x3C when ADDR = HIGH

#include <Wire.h> //BH1750 I2C Mode slave
uint16_t Lux=0;
void setup()
{ 
  Wire.begin();
  Serial.begin(9600);
}

void loop()
{
    Lux=0;
    Read_BH1750();
    Serial.print(Lux,DEC);     
    Serial.println(" LUX"); 

 delay(400);

}

void Read_BH1750() 
{
  byte buff[2];
  int i=0;
  Wire.beginTransmission(0x23);
  Wire.write(0x10);//1 Lux resolution time 120ms  
  Wire.requestFrom(0x23, 2 );
  while(Wire.available()){buff[i] = Wire.read(); i++;}    // receive one byte
  Wire.endTransmission(); 
  if(i==2){Lux=((buff[0]<<8)|buff[1])/(12/10);}
}